Carburetor for internal-combustion engines



06. 22, 1929. Q. SVENSSON 6 1,732,666

GARBURETOR FOR INTERNAL-COMBUSTION ENGINES Filed Nov. 22, 1926 AM IPatented Oct. 22, 1929 PATET OFFlQli'.

OSKAR S'VENSSON, OF DAGLOS'EN, SWEDEN GABBURETOE FOE INTERNAL-COMBUSTIONENGINES Application filed November 22, 1926, Serial No. 150,067, and inSweden December 19, 1925.

This invention relates to carburetors for internal combustion engines ofthat type, which comprises a controlling member, gen erally a swingableplate, which against the action of a spring is shifted by the aircurrent passing to or sucked into the working cylinder of the engine andat which an inlet opening for the fuel is provided in such a manner,that the fuel is carried away with he air passing the plate and mingledwith the same. The object of the said plate is that the same, every timethe mixture of fuel and air is sucked into the working cylinder, shouldbe brought into a certain position dependent on the number ofrevolutions of the engine and the intensity oi the sucking operationdependent on the said number of revolutions, in order that a mixturecontaining an unvariable percentage of fuel may be produced for eachstroke of the working piston. The said plate acted upon by the impact ofthe air in the one direction and by the spring in the oppositedirection, is caused to oscillate. The said plate, however, acted uponby its own weight and by the spring has a natural oscillation and forthat reason it may happen that the plate does not perfectly cmply withthe impulses resulting from air impacts but may, for instance, alreadyhave started on its way from its closed position, as the suckingoperation is started, which results in the plate being opened throughtoo great a distance, which on the other hand results in too small aquantity of fuel being carried with the air current and the mixturebeing too poor. It may also happen that the plate returns towards itsclosed position while the mixture is sucked into the cylinder, whichresults in the area of the air passage becoming too small and thus thesuction too forcible, which results in too rich a mixture. The object ofthe present invention is to remove the said and similar disturbances atthe mixing of the fuel charges. This is ettected by a retardingmechanism being combined with the controlling. member or the plate whichmechanism is so constructed that it permits the plate to be freelyopened through the distance, required by the air current, but retardsthe return stroke oi: the plate and thus prevents the same from fallingbackwards between the suction operations. Owing to this tact the platewill be held in a position substantially unvariable tor the number ofrevolutions respectively and at the transition for instance from agreater to a smaller number of revolutions the plate, acted upon by theretarding mechanism, will gradually move to a position corresponding tothe new, less -forcible suction or slighter pressure of the enteringair.

1 in the accompanying drawing shows in a side view an internalcombustion engine provided with a carburetor arranged in accordance withthis invention. Fig. 2 shows in a side view the retarding mechanism.

1, Figs. 1. and 2, is the ordinary air tube leading to the workingcylinder of the engine, 2 is the controlling member or swing-- ableplate, acted upon by a spring 3, which tends to move the plate to itsclosed position. At the part of the tube 1 against wl'iich plate 2 bearswhen being in its closed position a conduit i for the tliuel, benzine,opens, said conduit extending from a receptacle 5 which is provided withthe ordinary needle valve 7 controlled by a float 6 and regulating thelevel of the fuel provided in the receptacle 5. According to theinvention a rack 16, movable in guides 15, is connected with the arm 8of the controlling plate by means of a ink 1st, said rack 16 meshingwith a toothed wheel 18, which is rotatable on a shaft 17. On the saidtoothed wheel 18 a pawl 19 is provided, which engages a ratchet wheel 20fixed on the said shaft 17, to which two wings 21 also are fixed.

The described mechanism operates in the following manner. While air issucked into the working cylinder of the engine, bringing with itselffuel from the conduit 4, plate 2 is opened in a degree corresponding tothe intensity of the suction or to the pressure of the air current andrack 16 is moved downwards, while pawl 16 runs freely on the ratchetwheel 20. As the suction of the mixture of air and fuel into the workingcylinder ceases, spring 3 moves the plate 2 towards its closed positionand, consequently, the rack 16 is moved upwaii'ds. Paw], 19 then causesthe ratchet Wheel 20 and the wings 21 to rotate, which latter have aretarding influence on the return movement of the plate. During theoperation of the engine, plate 2 is subjected to repeated impulseseffected by the air passing to the Working cylinder and for that reasonwill remain in a substantially unvariable position, corresponding to theintensity of the suction operation. For that reason the mixture of airand fuel remains constant. At the transition to another number ofrevolutions plate 2 adjusts itself into the position corresponding tothe intensity of the suction, which then prevails. 1

The retarding device described above is simple and cheap and comprisesno valves, which may be stopped up and get out of order. The device isnot altered through variations of the temperature and moves easily whilethe plate is opened, because pawl 19 then runs idle.

I claim:

In a carburetor for internal combustion engines the combination of acontrolling member shifted by the air current passing to the Workingcylinder 01": the en ine, a yielding device adapted to return the saidcontrolling member, a supply conduit for the fuel and a retarding devicefor said controlling member, comprising a Wing-wheel, aratchet-mechanism connected to itsspindle and a motion transmittingdevice between the said controlling member and the ratchet-mechanism,said retarding device permitting the controlling member to be freelyopened but retarding its return movement towards its closed position, inorder that the controlling member may remain in substantially unvariableposition between air impulses of the same intensity and the mixture ofair and fuel thus kept constant.

In testimony whereof I have hereunto atfixed my signature.

OSKAR SVENSSON.

